1. Technical Field
The present invention relates to improvement of a winding insulation structure of a stator of an electromagnetic motor for securing an electrical insulation distance between a winding that is wound inside the slot of a stator and a stator iron core.
2. Description of Related Art
As an electromagnetic motor, for example, a brushless motor, a stepper motor, and the like are known.
A winding is wound inside the slot of a stator iron core of an electromagnetic motor with an electrical insulation member (hereinafter, simply referred to as “insulation member”) therebetween. In order to comply with foreign safety standards (UL, TUV standards, and the like), it is necessary that the windings have an insulation structure to ensure an electrical insulation distance between the winding and the stator iron core.
Since a process of windings the winding uses an automatic winding device, an opening portion of the slot is exposed. Thus, specifically, in a small electromagnetic motor, a creeping distance or a gap distance between the winding and the stator iron core is insufficient. Therefore, as a measure to ensure the electrical insulation distance between the winding and the stator iron core, an electrical insulation sheet (hereinafter, simply referred to as “insulation sheet”) is disposed between the winding and the insulation member built into the slot.
However, the insulation member built into the slot does not have a structure that allows the insulation sheet to be inserted therein. Thus, the insulation sheet must be manually placed between the winding and the insulation member and the placement of the insulation sheet requires time.
In the related art, various techniques relating to a winding insulation structure of the stator of the electromagnetic motor are proposed. For example, a winding insulation structure of an electromagnetic motor is disclosed in which the insulation sheet is easily inserted by providing a step in the insulation member so as to form a gap between the insulation member and the stator (see Japanese Patent No. 3819989).
Furthermore, a winding insulation structure of an electromagnetic motor is disclosed in which both end portions of an insulation member extending to a slot opening portion thereof are bent toward the inside of the slot and an insulation distance between a winding and a stator can be secured (see Japanese Unexamined Patent Application Publication No. 2002-281707).
However, in the technique disclosed in Japanese Patent No. 3819989, since the thickness of a portion in which the step for inserting the insulation sheet into the insulation member is provided is small, the insulation member is difficult to mold and is easily broken.
On the other hand, in the technique disclosed in Japanese Unexamined Patent Application Publication No. 2002-281707, it is difficult for the winding to be wound in a portion that is bent toward the inside of the slot and it is difficult to secure an area for the winding. Furthermore, since a winding process of the winding is necessarily performed such that the bent portion does not come into contact with a winding nozzle of the automatic winding device, the winding operation is difficult.